1. Technical Field
The present invention relates to a semiconductor device and a method for manufacturing a semiconductor device.
2. Related Art
As an electronic apparatus is downsized, a mounting space for an electronic component such as a semiconductor device which is mounted inside the electronic apparatus is decreased. Therefore, electronic components such as a semiconductor device are required to be further limited.
As a method for downsizing a semiconductor device, a method in which a semiconductor device is structured by layering semiconductor substrates (semiconductor chips) is proposed. In this method, semiconductor chips having the same functions as each other or semiconductor chips having different functions from each other are layered and wiring-connected with each other so as to achieve high density mounting of the semiconductor chips.
As a method for wiring-connecting the semiconductor chips, a method in which a through electrode (wiring electrode penetrating through the semiconductor chips) is provided on the semiconductor chips so as to wiring-connect the semiconductor chips is proposed.
In a case where the through electrode is electrically connected with an external terminal of the semiconductor device, a circuit element on the semiconductor chips may be damaged by static electricity inputted through the external terminal. Therefore, it is common to provide an electrostatic discharge (ESD) protection circuit which serves as a discharge path for electric charge inputted by static electricity.
However, an element used in the electrostatic discharge protection circuit (for example, a transistor or a diode) is difficult to be downsized and is usually larger than other circuit elements. Therefore, the electrostatic discharge protection circuit may degrade area efficiency of the semiconductor chips and degrade latitude of layout design (arrangement and wiring design) of the semiconductor chips.